KINGDOM ANIMALIA Phylum Porifera

Are Sponges Really Animals? Evidence suggests that sponges diverged early in the evolution of animals. Like other animals, they are multicellular. are heterotrophic. reproduce sexually. Unlike most other animals, they do not have a mouth or gut are sessile as adults. are not organized beyond the cellular level.

Question #1 Which of the following characteristics makes sponges unique among other animals? They are multicellular. They are heterotrophic. They do not have a mouth or gut. They are capable of reproducing sexually.

Sponge Organization A sponge is organized around its canal system, through which flagellated cells called choanocytes pump water. The body is supported by an endoskeleton of spongin (a form of collagen) and/or tiny spicules (made of calcium or silica).

Question #2 What type of cellular structure does a choanocyte use to help create the current inside a sponge? cilium flagellum spongellium pseudopodium

Question #3 The skeleton of a sponge includes tiny crystal-like structures that are called spongin spicules collagen choanocytes

Canal Systems Three major types: Asconoid-the simplest type of organization. Small and tube shaped, water enters the sponge through dermal pores and flows into the interior.

Asconoid

Canal Systems Syconoid-larger versions of asconoids, still having just a single osculum. However, the body wall is generally thicker and more complex with incurrent canals rather than simple pores.

Syconoid

Canal Systems Leuconoid-the most complex in design in that not all the chambers are flagellated. Water flowing in through incurrent canals is pumped through the chambers and expelled via one of a series of oscula. Best adapted to increase size.

Leuconoid

How do sponges eat? Sponges are suspension feeders. Water brings in food that is trapped by the choanocytes and transferred to the rest of the sponge by cells called amebocytes.

How do sponges eat? choanocytes amebocytes

Classification There are four classes of sponges: Calcarea-three- or four-rayed calcareous spicules (calcium carbonate); all three body forms

Classification Hexactinellida-six-rayed siliceous spicules (silica); generally syconoid

Classification Demospongiae-siliceous spicules (silica) that are not six-rayed, if any; all leuconoid

Classification Sclerospongiae-not recognized by all taxonomists. These sponges have siliceous spicules and a massive basal skeleton of calcium carbonate; all leuconoid

Question #4 Which of the four classes of sponges includes sponges with both silica and calcium carbonate in their skeletons? Calcarea Hexactinellida Demospongiae Sclerospongiae

Reproduction Asexual Reproduction Sexual Reproduction Asexual budding can produce new sponges. Sexual Reproduction Most sponges are hermaphroditic and can internally fertilize themselves.